Electrode catalyst for fuel cell, and fuel cell using same

Abstract

An electrode catalyst for a fuel cell, the electrode catalyst having high initial activity and being capable of long-term retention of said activity; and a fuel cell using the electrode catalyst for a fuel cell. The electrode catalyst for a fuel cell includes catalyst metal particles that include platinum or a platinum alloy, and carrier particles that carry said catalyst metal particles, wherein the carrier particles are a carbonaceous material having a cumulative pore volume of 0.10 cc/g or less in the diameter range of 2 nm or less, and a BET specific surface area of greater than 900 m2/g; and a fuel cell comprising the electrode catalyst for a fuel cell.

The invention claimed is: 
     
       1. An electrode catalyst for a fuel cell comprising catalyst metal particles containing platinum or a platinum alloy and carrier particles on which the catalyst metal particles are carried, wherein
 the carrier particles are a carbonaceous material having a cumulative pore volume of pores having a diameter of 2 nm or less of 0.01 cc/g or more and 0.09 cc/g or less, 
 a ratio of the cumulative pore volume of pores having a diameter of 2 nm or less to a total cumulative pore volume of the carbonaceous material of 0.01 or more and 0.10 or less, and 
 a BET specific surface area of more than 900 m 2 /g. 
 
     
     
       2. The electrode catalyst according to  claim 1 , wherein the carbonaceous material has a cumulative pore volume of pores having a diameter of 6 nm or less of 0.25 cc/g or more. 
     
     
       3. The electrode catalyst according to  claim 1 , wherein the total cumulative pore volume of the carbonaceous material is 1.0 cc/g or more. 
     
     
       4. The electrode catalyst according to  claim 1 , wherein the BET specific surface area of the carbonaceous material is 1500 m 2 /g or less. 
     
     
       5. The electrode catalyst according to  claim 1 , wherein a ratio of a number of the catalyst metal particles having a diameter of 2 nm or less is 23% or less with respect to a total number of the catalyst metal particles. 
     
     
       6. The electrode catalyst according to  claim 1 , wherein a number average particle size of the catalyst metal particles is 2.8 to 4.0 nm. 
     
     
       7. A fuel cell comprising the electrode catalyst according to  claim 1 . 
     
     
       8. The electrode catalyst according to  claim 2 , wherein the total cumulative pore volume of the carbonaceous material is 1.0 cc/g or more. 
     
     
       9. The electrode catalyst according to  claim 2 , wherein the BET specific surface area of the carbonaceous material is 1500 m 2 /g or less. 
     
     
       10. The electrode catalyst according to  claim 3 , wherein the BET specific surface area of the carbonaceous material is 1500 m 2 /g or less. 
     
     
       11. The electrode catalyst according to  claim 2 , wherein the cumulative pore volume of pores having a diameter of 6 nm or less of the carbonaceous material is 1.20 cc/g or less. 
     
     
       12. The electrode catalyst according to  claim 1 , wherein the cumulative pore volume of pores having a diameter of 6 nm or less of the carbonaceous material is 0.50 cc/g or more and 1.00 cc/g or less. 
     
     
       13. The electrode catalyst according to  claim 1 , wherein a cumulative pore volume of pores having a diameter of 10 nm or less of the carbonaceous material is 0.50 cc/g or more and 1.50 cc/g or less. 
     
     
       14. The electrode catalyst according to  claim 1 , wherein a cumulative pore volume of pores having a diameter of 10 nm or less of the carbonaceous material is 0.70 cc/g or more and 1.00 cc/g or less. 
     
     
       15. The electrode catalyst according to  claim 1 , wherein the total cumulative pore volume of the carbonaceous material is 1.10 cc/g or more and 2.00 cc/g or less. 
     
     
       16. The electrode catalyst according to  claim 1 , wherein the total cumulative pore volume of the carbonaceous material is 1.20 cc/g or more and 1.50 cc/g or less. 
     
     
       17. The electrode catalyst according to  claim 1 , wherein the ratio of the cumulative pore volume of pores having a diameter of 2 nm or less to the total cumulative pore volume of the carbonaceous material is 0.01 or more and 0.08 or less. 
     
     
       18. The electrode catalyst according to  claim 1 , wherein the ratio of the cumulative pore volume of pores having a diameter of 2 nm or less to the total cumulative pore volume of the carbonaceous material is 0.01 or more and 0.06 or less.